What is Muscle Maturity?

“Muscle maturity” is often mentioned when comparing bodybuilders competing on stage. Typically, the term is used to explain why a young bodybuilder has a harder time reaching the hard and grainy look of someone older, or otherwise much more experienced. Preaching the possibility of gaining muscle maturity is often an effort to reassure a new bodybuilder of future potential. However, actually defining muscle maturity is quite debatable – exactly what it is depends on whom you ask.

Many fitness publications, even accredited medical journals outlining the principles of animal growth and development, construe muscle maturity as a maximization of muscle fiber size. Strength athletes frequently – often erroneously – interpret a stubbornness to build muscle and strength as reaching peak genetic potential. Everyone begins weight training at various degrees of genetic endowment, but truly maximizing one’s potential for muscle growth is at least as hard to define as muscle maturity itself. Muscle gains usually stop due to insufficient nutritional habits or poorly designed exercise programs – both parameters must evolve with the athlete. Furthermore, failing to train the body’s muscular systems symmetrically can stall results; such as favoring upper-body training while ignoring the lower extremities. Symptoms of overtraining syndrome result in chronic fatigue and drops in limit strength. Also, administering anabolic-androgenic steroids increases blood androgen levels to supra physiological values. Exogenous hormone use supports muscle acquisition beyond genetic predispositions. If muscle maturity is synonymous with reaching genetic limits, administering AAS for an ergogenic effect would blur this defining moment.

Some fitness enthusiasts connect muscle maturity to changes in neuromuscular coordination. When beginners first start bodybuilding, muscles quiver under loads due to a lack of properly developed motor control. In time, consistent rehearsal using proper form leads to less involvement from antagonist and supportive muscles. After years of resistance training, muscular bodybuilders develop a capacity to execute movements with maximum intensity; while less conditioned individuals have a harder time focusing efforts. Consistent and progressive training results in more efficient agonist muscle activation, stronger contractions and greater pumps. This adaptation to exercise eventually allows sudden and dramatic increases in muscle strength, size and definition. However, this pivotal change in a bodybuilder’s athletic progression more accurately explains the process of muscle memory – not maturity.

Muscle hardness seems to vary amongst individuals, based on age and exposure to strain. The basic make up of muscle tissue is consistent amongst all mammals; it’s composed of tiny tube-like fibers with the ability to contract, either voluntarily or involuntarily. Young and generally inactive muscle is soft; as illustrated at the local butcher shop by comparing veal to meats obtained from matured cattle. Veal is known for its tender texture and originates from inactive and young calves. To potentiate this softening affect prior to slaughter, some farms keep calves in small containers to restrict their movements. It seems reasonable to associate muscle maturity with a threshold where muscle loses tenderness.

In April 2007, the Department of Animal and Food Science conducted a study examining the tenderness and oxidative stability of post-mortem muscles from cows of various ages. The researchers confirmed meat is most tender in young animals and muscle fibers become tough and hard when subject to a lot of muscular action; according to biopsies obtained from necks and leg tissue. Advanced maturation not only intensified cow meat toughness but also lowered its oxidative stability. Collagen, the basic substance of the connective tissue bundling groups of muscle fibers together, is known to breakdown easier in young and tender muscle tissue, when boiled in water. This fibrous protein gets tougher with age due to an increasing number and type of cross-links. In this respect, muscle maturity could refer to a change in the muscle tissue’s architecture; more specifically, a change in collagen solubility.

At low body fat percentages, the thickness of encompassing tissue will have the greatest influence over the outward appearance of underlying muscle. Enlarging muscle fibers with progressive resistance training stretches surrounding fascia and thins out the skin. Stretch marks occur when skin stretches fast enough to rupture elastic fibers. Skin thickness varies greatly between different body sites. The thinnest epidermis lies over the abdominals and thorax. The arms and legs are generally wrapped in the thickest layers of skin – especially over the palms and the soles of feet. Changes in epidermal thickness by age are difficult to measure but varies greatest in older populations. Through all ages, men have thicker skin than women. In clinical studies, men’s skin has demonstrated a gradual thinning with advancing age, whereas women’s skin thickness remains more constant until the post menopausal years, after which it also declines. Hormonal patterns could play a significant role – androgens in particular. Interestingly, both sexes exhibit a linear decrease in skin collagen throughout a lifetime. Collagen contributes to skin’s smooth, plump appearance – beauticians are always on the look for ways to boost collagen levels and repair collagen damage. For bodybuilders trying to obtain a hard and grainy appearance, the natural decrease in skin collagen might not be so bad. Once again, collagen seems to play a role in obtaining a hard and grainy look.

What is muscle maturity? Bodybuilders tend to associate muscle maturity with achieving a tough and serrated appearance at low body fat percentages. This visual effect is likely to occur only after proper motor skills are developed and muscle adapts to intense training demands. Some trainees obtain the look faster than others, but genetic anomalies set aside, the phenomenon is most often realized after many years of conditioning muscles to progressive overloads. Subsequent changes in collagen, within muscle and skin, may play major roles.